Retaining Walls in Mount Pleasant, Christchurch
Top Retaining Walls Christchurch works throughout Mount Pleasant. Failed and leaning walls assessed and rebuilt, earthquake damage that was never properly repaired, engineered walls on steep sections, and driveway retaining where the drive is benched into the hill.
- Housing here: Hillside homes, much of it on placed fill
- Most common job: Earthquake remediation and rebuilds
- Free site visit and a fixed written quote
- Drainage and consent handled, not extra
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Four quick questions. Most quotes come back within a couple of days.
Mount Pleasant carries more post earthquake retaining work than almost anywhere in the city. Surface cracking was identified in fill material at Quarry Road on the lower slopes after the February 2011 event, and the wider Port Hills investigations documented mass movement across the developed slopes. A lot of walls here were patched at the time and are failing again now.
Non engineered fill and Mount Pleasant retaining walls
Many Mount Pleasant sections were formed decades ago by cutting into the hill on one side and filling on the other to create a level platform. Where that fill was placed without engineering it behaves very differently to the undisturbed loess beside it.
That distinction matters on every job here. A wall on the cut side is holding undisturbed ground. A wall on the fill side is holding material somebody tipped there, and that is the side that moved in 2010 and 2011.
What we find on earthquake damaged retaining walls here
Retained fill that settled behind flexible timber pole walls, leaving the wall upright and the ground behind it a hundred millimetres lower. Block walls that rotated at the base and never came back. Non engineered rock facings that collapsed outright.
Where the ground itself moved rather than the wall, replacing the wall does not fix anything. We say so and recommend a geotechnical engineer rather than quoting a structure that will move again.
Rebuilding Mount Pleasant retaining walls to current guidance
A wall rebuilt here today is designed to the MBIE Canterbury guidance rather than to whatever was normal when the original went in. Where the geometry allows it we prop or buttress rather than building a pure cantilever, because the Canterbury evidence shows those walls damaged less.
Retaining wall jobs we get called out for in Mount Pleasant
- Retaining Wall Builders in Mount Pleasant, free site visit and a fixed written quote.
- Retaining Wall Repair in Mount Pleasant, we find out why it moved before quoting anything.
- Gabion Retaining Walls in Mount Pleasant, drain freely, so no water builds up behind them.
- Retaining Wall Replacement in Mount Pleasant, old wall removed and disposed of.
- Engineered Retaining Walls in Mount Pleasant, for walls over 1.5m or carrying any surcharge.
Mount Pleasant sits on the same run as Sumner, Redcliffs and Heathcote Valley, so we are usually in the area anyway.
Retaining walls in Mount Pleasant: common questions
My Mount Pleasant wall was repaired after the earthquakes and is moving again. Why?
Commonly because the original repair addressed the wall and not the ground, or because settled fill behind it was never properly reinstated.
Is my section on cut or fill?
Often both, and they behave differently. Working out which side of the platform your wall is on is one of the first things we look at.
How can I tell whether my section is cut or fill?
Often it is both, with the house sitting on a platform formed by cutting into the hill on one side and filling on the other. The council file and any subdivision records are the reliable answer, and it is one of the first things we look at, because a wall on the fill side is a different design problem to one on the cut.
Is a geotechnical report always needed in Mount Pleasant?
Frequently, given the slope, the loess and the earthquake history recorded on many files here. Whether it is required depends on the wall height, the surcharge and what council already knows about the site, and we check the file before committing you to the cost.
Get a retaining wall quote in Mount Pleasant
Free measure, fixed written price, and an honest call on repair against replacement.
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Four questions and you are done.